Advanced wastewater treatment processes are known to be an effective tool for reducing micropollutant discharge into the aquatic environment. Nevertheless, some processes such as ozonation result in stable transformation products with often unknown toxicity. In the present study, effluents from different steps of advanced treatment were compared for their aquatic toxicity. Lumbriculus variegatus, Daphnia magna and Lemna minor were chronically exposed on-site in flow-through tests and effects on survival, growth and reproduction were assessed. Additionally, the impact of treated wastewater on the immune response of D. magna was investigated by challenging the daphnids with a bacterial endoparasite. Conventionally treated wastewater reduced reproduction of L. variegatus, but did not affect D. magna and L. minor with regard to survival, growth, reproduction and, for D. magna, parasite resistance. Instead, parasite susceptibility was significantly reduced in D. magna exposed to conventionally treated as well as ozonated wastewater in comparison to control daphnids. Results obtained with the three test species did not provide clear evidence that wastewater ozonation led to increased aquatic toxicity. The reduced reproduction of L. variegatus could be linked to elevated concentrations of ammonium and nitrite that have most likely resulted from treatment failures.
For additional information, see the publication in Aquatic Toxicology:
Schlüter-Vorberg, L., Knopp, G., Cornel, P., Ternes, T., Coors, A. (2017). Survival, reproduction, growth, and parasite resistance of aquatic organisms exposed on-site to wastewater treated by advanced treatment processes. Aquatic Toxicology 186, 171-179.
The study was performed within the project Transrisk (FKZ 02WRS1275), which was funded by the German Federal Ministry of Education and Research (BMBF) within the framework ‘Risk management of emerging compounds and pathogens in the water cycle’ (RiSKWa).
For further new publications, see ECT’s publication list.